The hills on Los Angeles County’s northern frontier are barren now, but spring will soon coax a brilliant display of orange, purple and yellow wildflowers across miles of the Grapevine region of Interstate 5.

The annual floral show is one that few sites in Southern California can match.

DREAMSCAPE: Wildflowers, including California poppies, lupine, owl’s clover, goldfields and desert suncups, blanket slopes and canyons in Gorman. Developers hope to construct one of the largest planned communities in Los Angeles County history nearby.

But some worry that development pressures threaten the flower fields in the Gorman Hills, the same landscape that inspired environmental artist Christo to mimic the spring bloom in his famous “Umbrellas” project in October 1991.

Developers hope to construct one of the largest planned communities in Los Angeles County history, with 23,000 homes on a portion of the vast expanse of neighboring Tejon Ranch. A Tustin-based builder is also seeking permits for 191 homes on the northern edge of the wildflower site.

Eager to stay ahead of the building boom, a Los Angeles city planning official and a group of his UCLA Extension students advocate establishing a vast, new Gorman wildflower preserve that would stretch several miles east of Interstate 5 and north of California 138.

MOSAIC: Visitors hike in the hills above Gorman Post Road, just north of I-5. The proposed perserve would protect 2,800 acres.

Planner Mike O’Brien said he has always admired the spring bloom on travels to Northern California. He sees the preserve as an antidote to urban sprawl creeping up the Tehachapi Mountains, connecting the Los Angeles Basin to the San Joaquin Valley.

“Whole new communities are being built in the middle of nowhere,” he said. “That’s urban sprawl. Do we really want everything built from San Clemente to Bakersfield?”

Among the proposed development projects is Centennial, a “new town” of 70,000 people that would be built on Tejon Ranch, which straddles Los Angeles and Kern counties. Other plans call for building hundreds of more homes near the top of Tejon Summit near Lebec.

“This entire area is really about to be changed forever because of development,” said Patric Hedlund, managing editor of the Mountain Enterprise newspaper in Frazier Park. “It represents economic opportunity, but people came here to enjoy places like the wildflower lands.”

Potential advocates for a preserve include the California Native Plant Society and the state parks department, and more are expected, O’Brien said. Residents in the mountain communities are just learning about the proposal from local newspaper articles and town hall meetings.

But there are many obstacles to creating a wildflower preserve. Cost is chief among them.

No one knows just how much money would be needed to establish a preserve, but the price tag would probably be millions of dollars. Most of the money would go toward purchasing developable properties.

The UCLA students are counting on organizations such as the Nature Conservancy, the Trust for Public Land and the Sierra Club to step forward and work with local officials to raise money for the project. The Gorman Hills are a checkerboard of parcels owned by 22 parties, not all of whom may want to relinquish their parcels.

Matthew Shaffer, spokesman for the Trust for Public Land, a nonprofit group that promotes open space, said the trust has championed student projects before, most notably in Atlanta, where a term paper by a Georgia Tech student became the blueprint for a network of parks, trails and commuter rail lines.

“It’s a familiar proposition to take a vision worked on by students and make it happen,” Shaffer said of the UCLA proposal. “It sounds like something we might want to consider.”

The UCLA students spent the fall quarter preparing their report, which is a roadmap for carving out 2,800 acres of flower-dappled hills at the junction of I-5 and California 138 southeast of Gorman. They advocate building trails, interpretive signs and a visitor center.

“For generations, this spring display has drawn lovers of wildflowers, particularly devotees of the state flower — the California poppy,” the students’ report states. “Conventional wisdom holds that man’s hand has weighed so heavily on the land that little remains of California’s original state. Yet … Gorman Post Road is considered one of the best wildflower sites in Southern California.”

In winter, the Gorman Hills are tawny heaps of nothingness, dotted with power poles, barbed-wire fences and juniper bushes. But the hills looming over Gorman Post Road, a country lane astride a slit in the San Andreas fault, explode in color when spring conditions are right.

Motorists park their cars and step into a dreamscape of poppies, lupine, owl’s clover, goldfields and desert suncups that spill over slopes and into canyons.

June Furman, 72, has lived on Gorman Post Road for decades. She said she has to shoo away tourists who cross her 13-acre ranch to see the wildflowers in springtime. She worries that more houses in the area would spoil the land.

“I’d rather see wildflowers than houses,” she said.

Builders are carefully studying the Gorman wildflower preserve proposal. Jeff Haspell, project manager for Rox Consulting, said the Tustin company wants to build homes on 10% to 15% of the land identified for the preserve. But he said the two projects would not conflict.

“This is going to be easy to work out,” Haspell said. “There’s lots of room to work and be flexible. I don’t see a problem that won’t allow both to work together.”

Barry Zoeller, spokesman for Tejon Ranch, which seeks to develop 5% of its substantial land holdings in the Tehachapis, said he also doesn’t see a problem with establishing a preserve. “We see the value in it,” he said. “It’s consistent with what Tejon Ranch is.”

Plans to develop houses or the wildflower preserve in the Grapevine have lately engrossed the mountain communities’ residents, who realize, after 50 years of sitting on the sidelines as growth swept over Southern California, that change is coming to their hills.

Said local newspaper editor Hedlund of the proposed flower preserve: “People are beginning to talk for the first time about what ecotourism opportunities there might be. The preserve could be a real jewel in the center of that.

“It’s like we’re at this trembling moment, to invent new understandings of what is economically viable, and yet there’s this race against time.”